Remove Telemetry.Period, it was too magical to some

- fix Telemetry.wallclock: it shouldn't return since epoch
- improved snap() subroutine, now also allows pushing to a given array
- added periods() subroutine, for generating a Seq of Telemetry::Period objects

lib/Telemetry.pm6

@@ -11,16 +11,13 @@ class Telemetry {
 
     my num $start = Rakudo::Internals.INITTIME;
 
-    multi method new(Telemetry:) { nqp::create(self).SET-SELF }
-
-    method SET-SELF() {
+    submethod BUILD() {
         my \rusage = nqp::getrusage;
         $!cpu-user = nqp::atpos_i(rusage, nqp::const::RUSAGE_UTIME_SEC) * 1000000
           + nqp::atpos_i(rusage, nqp::const::RUSAGE_UTIME_MSEC);
         $!cpu-sys  = nqp::atpos_i(rusage, nqp::const::RUSAGE_STIME_SEC) * 1000000
           + nqp::atpos_i(rusage, nqp::const::RUSAGE_STIME_MSEC);
         $!wallclock = nqp::fromnum_I(1000000*nqp::sub_n(nqp::time_n,$start),Int);
-        self
     }
 
     proto method cpu() { * }
@@ -53,33 +50,10 @@ class Telemetry {
 
     proto method wallclock() { * }
     multi method wallclock(Telemetry:U:) is raw {
-        nqp::fromnum_I(1000000 * nqp::time_n,Int)
+        nqp::fromnum_I(1000000 * nqp::sub_n(nqp::time_n,$start),Int)
     }
     multi method wallclock(Telemetry:D:) is raw { $!wallclock }
 
-    proto method Period() { * }
-    multi method Period(Telemetry:U \SELF:) is raw {
-        if nqp::iscont(SELF) {
-            SELF = SELF.new;
-            nqp::create(Telemetry::Period)
-        }
-        else {
-            die "Must use container of type Telemetry"
-        }
-    }
-    multi method Period(Telemetry:D:) is raw {
-        my int $cpu-user  = $!cpu-user;
-        my int $cpu-sys   = $!cpu-sys;
-        my int $wallclock = $!wallclock;
-        self.SET-SELF;
-
-        Telemetry::Period.new(
-          nqp::sub_i($!cpu-user,$cpu-user),
-          nqp::sub_i($!cpu-sys,$cpu-sys),
-          nqp::sub_i($!wallclock,$wallclock)
-        )
-    }
-
     multi method Str(Telemetry:D:) {
         $!wallclock ?? "$.cpu / $!wallclock" !! "cpu / wallclock"
     }
@@ -141,6 +115,18 @@ multi sub infix:<->(Telemetry:D $a, Telemetry:D $b) is export {
     )
 }
 
-sub snap() is export { Telemetry.new }
+my @snaps;
+proto sub snap(|) is export { * }
+multi sub snap(--> Nil) { @snaps.push(Telemetry.new) }
+multi sub snap(@s --> Nil) { @s.push(Telemetry.new) }
+
+proto sub periods(|) is export { * }
+multi sub periods() {
+    (1..^@snaps).map: {
+        LAST @snaps = ();
+        @snaps[$_] - @snaps[$_ - 1]
+    }
+}
+multi sub periods(@s) { (1..^@s).map: { @s[$_] - @s[$_ - 1] } }
 
 # vim: ft=perl6 expandtab sw=4